The general objective is to determine the biological bases of an abnormal behavior that is induced by central nervous system lesions. Three different lesions produce the same abnormal behavior: lesions in the rostral part of the cerebral neocortex, pontile tegmentum and the middle cerebellar peduncle. The abnormal behavior consists of the appearance of fragments of the grooming repertoire when the skin is touched. These fragments are consummatory behaviors that are occurring in complete isolation from the normally preceding orienting components. The lesions, then, produce a disintegration in appetitive and consummatory grooming behaviors. Because the quantitative extent of the behavioral abnormality varies with the seasons of the year, with a rhythmic trend similar to the glucocorticoid rhythm, experiments are proposed to determine what environmental event is controlling the rhythms. Previous data have established that the superior colliculus is mediating the abnormal behavior, and studies are proposed to determine the role of the superior colliculus in the mediation of the environmental event that is controlling the rhythms and in the mediation of grooming behavior. To further specify the anatomical substrate of the grooming behavior, both chronic and acute ablation studies are proposed. Acute ablation studies are possible because some aspects of the abnormal behavior appear under surgical anesthesia. Thus, with a combination of electrophysiological and ablation methods, the minimal structural basis for the abnormal grooming behavior will be determined.